Neuropathy a New Underappreciated Cause of Erectile Dysfunction

"To our knowledge, this is the first study to assess the whole peripheral nerve fibre spectrum in a non-selected group of patients with erectile dysfunction," said the study's lead author, Consuelo Valle Antuña, MD, from the Department of Neurophysiology at the Hospital Universitario Central de Asturias in Oviedo, Spain, in a press release. "Our findings underline the importance of clinicians carrying out neurophysiological tests on patients with ED, particularly in the pelvic area."

Ninety men participated in the study. The average age of the patients was 54 years, with 10% of the men being younger than 40 years and 2.2% older than 70 years. Cardiovascular disease was diagnosed in 30%, neurogenic findings in 16%, diabetes in 15.9%, and psychopathology in 7.3% of the participants; no risk factors were identified in 11.1%.

Patients underwent a battery of neurophysiological tests and filled out the 5-item version of the International Index of Erectile Function (IIEF) and the Neuropathy Symptom Score (NSS). Patients scoring poorly on the NSS also scored more poorly on the IIEF (P = .015), and they needed ED therapies (e.g., prostaglandin, penile prostheses) that were more aggressive than oral type-5 phosphodiesterase inhibitors (P = .0001).

Pelvic floor electromyography revealed signs of chronic axonotmesis in 48% of the participants, and was bilateral in 20%. Polyneuropathy was identified in approximately 38% of the patients. Nine percent of the patients had small fiber neuropathy or damage to the small unmyelinated peripheral nerve fibers, and 14.4% had pudendal neuropathy, involving the somatic nerve in the pelvic region. Sympathetic skin response tests revealed far more response alterations in the penis than the hand or foot. Chronic axonotmesis was associated with NSS scores (P = .0038), but there was no link between neurophysiological findings and the IIEF.

The authors conclude that "up to now, the impact of peripheral neuropathy on the pathogenesis of ED has been underestimated.... Day-to-day clinical practice should, in future, optimize the assessment of pelvic small fiber function."